Mike Loucks
John Carrico
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Today IBEX got within 100,000 km of the Moon at apogee. The distance was roughly 93,000 km and periselene was at 5 Nov 2008 20:55:04 UTC.
I would like to take this opportunity to honor my friend and mentor Chauncey W. Uphoff (1940-2004) who taught me most of what I know and without whom I would not be doing what I’m doing today.
Cheers my friend, I know where you were at 20:55:04 UTC. “Riding the spacecraft”.
Here’s a picture from the 1st annual Astrogator’s Guild meeting in July.
(From the AGI Astrogator Wiki)
You can use the VGT sunlight vector to do this. Make a vector mag calc object that gives the magnitude of the sunlight vector (the sunlight vector is under Templates - Satellite. Create a user select stopping condition, and set its calc object to the sunlight vector magnitude calc object you just created. For an enter direct sunlight stopping condition, set the trip value to 1, and the criterion to Cross Increasing. For an exit direct sunlight stopping condition, set the trip value to 0.999999 (make sure the tolerance is smaller than the difference between the trip value and 1), and the criterion to Cross Decreasing.
If you want to stop when exiting or entering penumbra, use similar stopping conditions with the trip value set to zero. (We’ll see default stopping condition like this in 8.2)
It’s now available online:
For your viewing please, we have added several VDF files to the right column. Please see the “Lunar Trajectory Webinar VDFs”. These files are the scenarios that will be shown during the webinar. Also be aware that the VDF format is a compression scheme for STK scenarios as well, and that if you have an STK/Astrogator license, you can open these files from within STK and have full access to the mission control sequences used to create these missions.
As always, feel free to ask questions about the scenarios.
If you hadn’t heard, the entire trajectory to Pluto (New Horizons) was planned and is being flown by Astrogator. They just passed Jupiter (gravity assist) and are on their way to Pluto. They took a ton on of images as they passed.
Good job everyone!
Also remember, it’s the fastest thing ever built by man! only nine hours from the Earth to the Moon when it launched!
After they plan a maneuver they check it with JPL trajectory software and things are going perfectly!
Here’s the home page with a screen snap from STK:
Some links from the New Horizons home page:
Pluto-Bound New Horizons Spacecraft Gets a Boost from Jupiter
Fyi, they also do the maneuver planning for Messenger with Astrogator. JPL’s CATO is used for the multiple gravity assist trajectory design, and the high-fidelity maneuver planning and gravity assists are planned with Astrogator. See Messenger
There are lot’s of STK animations there, too!
John
2 Papers have been added to a new “Published Papers” section. The first was the Toronto Lunar Landing paper that John and I and Tim (Carrico) wrote in 2005, and the other is a paper that was written in 2006 on some proximity operations work done with fuzzy logic. Check them out.
Today I’m adding several tutorials from the Day 4 Astrogator training. In particular, you’ll see an Earth-Moon libration point trajectory, a Mars trajectory and a Jupiter-flyby. I plan to add the VDF files for each of these scenarios so that users without an STK license can see the trajectories.